Joint lock control



M. WALTERS JOINT LOCK CONTROL Nov. 5, 1968 2 Sheets-Sheet 1 Filed June20. 1966 Mitchell Walters INVENTOR.

Nov. 5, 1968 M. WALTERS JOINT LOCK CONTROL 2 Sheets-Sheet 2 Filed June20, 1966 Mi fchel/ Wa/fers 1N VENTOR.

BY MAY Ammlt]:

United States Patent 3,408,660 JOINT LOCK CONTROL Mitchell Walters,Lexington, Ky., assignor 0f forty-nine percent to Edgar W. Borchert,Lexington, Ky. Filed June 20, 1966, Ser. No. 558,665 Claims. (Cl. 31.2)

The instant invention is concerned with artificial limbs, and moreparticularly relates to a joint lock and control therefor.

It is a primary object of the instant invention to provide a pneumaticcontrol particularly adapted for use in conjunction with the knee jointof an artificial leg with the control being operatively responsive todisengage the knee lock upon the application of pressure on the toeportion of the foot associated with the artificial leg.

Another significant object of the instant invention resides in theincorporation of means within the pneumatic control for varying thedegree of pressure necessary to actuate the control and release thelock.

Further, it is a significant object of the instant invention to providea joint lock control wherein the pneumatic control is deactivated uponthe toe leaving the ground with the lower leg member swinging freelyuntil brought into longitudinal. alignment with the upper leg member atwhich time the lock is automatically engaged.

In conjunction with the above object, it is an object of the instantinvention to provide a knee joint construction which will remain lockedand stable from a point just prior to the heel striking the ground untilthe full weight is shifted to the toe portion of the foot immediatelyprior to the toe leaving the ground, with the lock automaticallyreengaging as the leg is swung forwardly.

Another highly significant object of the instant invention, inconjunction with the preceding object, is the pro-- 'vision of a jointlock and control therefor which will enable the user thereof to maintainany normal gait with the control and lock operating regardless ofwhether the user is walking slowly or running.

Basically, in achieving the above objects, the joint construction andcontrol therefor is to include a keeper mounted on the upper leg member,an elongated mount aflixed to the lower member and pivotally engagedwith the upper leg member, a latch pivotally mounted on the lower legmember for engagement with the keeper, means for resiliently biasing thelatch into engagement with the keeper, and a pneumatic system forwithdrawing the latch. The pneumatic system is to include a first airsack mounted in a manner whereby an expansion thereof will, through asuitable linkage, withdraw the latch, with the expansion of the sackbeing directly responsive to the collapse of an air tube communicatedsimilar sack located in the vicinity of the toe portion of the foot. Inaddition, a suitable hand pump is communicated with the air sack systemso as to provide a means for varying the weight on the foot mounted airsack necessary to release the latch.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a side elevational view of an artificial leg having a jointand control construction of the instant invention utilized therein;

FIGURE 2 is a front elevational view of the leg;

FIGURE 3 is an enlarged cross-sectional view taken substantially on aplane passing along line 33 in FIG- URE 1;

FIGURE 4 is an enlarged vertical cross-sectional view 3,408,660 PatentedNov. 5, 1968 taken substantially on a plane passing along line 4--4 inFIGURE 2;

FIGURE 5 is an enlarged perspective view of a portion of the joint andcontrol construction; and

FIGURE 6 is a bottom perspective view of the upper leg member.

Referring now more specifically to the drawings, reference numeral 10 isused to generally designate the artificial limb incorporating the jointconstruction and lock control of the instant invention, this limb 10 inmost instances comprising an artificial leg. The limb or leg 10 willinclude upper and lower leg members 12 and 14 pivotally joined in thearea of the knee for a flexing thereof in the manner of a normal leg.

The lower leg member 14 includes an enlarged vertically elongated hollowchamber 16 therein, this chamber opening upwardly between two verticallyprojecting side extensions or cars 18 which pivotally receive thereduced lower end portion 20 of the upper leg 12 therebetween. A rigidmount 22 is used to pivotally interconnect the upper and lower legmembers 12 and 14. This mount 22 consists of a pair of verticallyelongated spaced side plates 24 having reversely directed lower endportions 26 thereon rigidly engaged with an enlarged flat mounting discor member 28 which is fixedly bolted against the rear wall of thechamber 16 by suitable bolt means 30 extending through the rear wall ofthe lower leg member 14 and threaded through the member 28. The mountside plates 24 have the upper portions thereof received within adownwardly opening chamber 32 defined within the upper leg member 12with the upper ends of the mount side plates 24 being both forwardly andupwardly inclined and provided with enlarged pivot pin receivingapertures 34 therethrough for the reception of the pivot pin 36. Thispivot pin 36 has the opposite end portions thereof received both throughthe body of the lower end portion 20 of the upper leg member 12,suitably apertured as indicated by reference numeral 38 in FIGURE 6, andthrough the vertically projecting lower leg member cars 18 which receivethe lower portion 20 of the upper leg member 12 therebetween. It will ofcourse be appreciated that the opposite ends of the pivot pin 36 areprovided with suitable enlargements so as to retain the pin in position.In this manner, the upper and lower leg members 12 and 14 are free topivotally swing relative to each other within the limits of the upperchamber 32. Incidently, it will be noted that the side plates 24 of themount 22 are rigidly interbraced by a pair of transversely extendingplates 40 and 42, the plate 40 being positioned coplanar with theforward edges of the side plates 24 within the upper leg portion chamber32, this plate 40, in addition to rigidifying the mount 22, also actingas a limit, through engagement with the forward wall of the chamber 32,to a forward swinging of the lower leg member 14 to its longitudinallyaligned position with the upper leg member 12. The rearward swinging ofthe lower leg member 14 can be limited in any suitable manner such as byan engagement of the rear edges of the side plates 24 with the rear wallof the chamber 32.

The lower end of the upper leg member 2 is provided with a keeper 44which includes a keeper opening 46 therein, a forwardly directedmounting plate portion 48 underlying the forward portion of the lowerend of the leg member 12 to which it is rigidly affixed as by screwmembers 50, and a rearwardly directed bearing surface defining plate 52terminating in an upwardly directed flange 54. It will of course beappreciated that the upper leg member 12 is recessed upwardly orinwardly of the keeper opening 46 for the reception of the hook end 56-of the latch or latch member 58.

The latch 58 consists of a horizontally elongated bar v n an. va dlrd essi a s secured, adjacent the uppert end thereof, by pin means 62 betweenthe side plates 24 of the mount 22. The forward end of the latchdefining bar is also upwardly directed so as to form the hook or hookportion 56 which is received within the keeper hole 46. This hook 56includes a vertical rearwardly directed abutment face 64 whichnecessitates a complete withdrawal of the hook 56 so as to release thelock. Further, the upper end of the hook or hook portion 56 itself isrounded so as to define a friction reducing bearing surface for movementover the lower surface of the plate 52 rearward of the keeper hole 46 asshall be described presently.

It will be noted that the position limiting cross brace 40 of the mount22 engages against the forwardwall of the chamber 32 in conjunction withthe engagement of the book 56 within the keeper opening 46, therebyincreasing the stability of the locked joint and eliminating anyundesirable loose play therein. Along these same lines, it will be notedthat the longitudinal distance between the hoop 56 and the upwardlyprojecting rear portion 60 of the latch 58 is of a size so as to justreceive the rearwardly extending plate portion 52 of the keeper" 44therebetween.

The latch 58 is to be constantly resiliently biased toward engagementwith the keeper 44 by means of at least one elongated coiled tensionspring 66 engaged between the lower rear'corner of the latch 58 and thelower rear portion of the mount 22, as best seen in FIGURE 4. In thismanner, any downward and rearward swinging of the latch 58 will beresisted by the spring 66 with the removal of the latch moving forceresulting in an immediate return of the latch toward its engagedposition.

The release of the latch 58 is to be effected through a pneumaticcontrol system which includes upper and lower expansible andcontractible air bellows or sacks 68 and 70. The upper sack 68 ismounted between upper and lower hingedly engaged plates 72 and 74. Theupper plate 72 underlies the forward portion of the lower end of themount 22 and includes a vertically directed flange 76 which is fixedbetween the mount side plates 24 by a transversely extending pin 78,thereby securing the upper plate 72 which, as will be appreciated fromFIGURES 3 and 5, is of a width greater than that of the mount 22. Thelower plate 74 is engaged, through suitable hinges 80, to the rear edgeof the plate 72 for a swinging movement relative thereto. This plate 74,of a size and shape substantially conforming to that of the upper plate72, has a pair of vertically directed integral legs 82 on the forwardedge thereof. These legs are in turn pivotally engaged to a flat strap84 by a rigid connecting wire or clip 86, a similar wire or clip 88being used to pivotally engage the strap 84 with the forward end of thelatch 58 below the hook portion 56. Thus, it will be noted that adownward movement of the lower plate 74 will effect, through thelinkages 84, 86 and 88, a downward pivoting of the forward end of thelatch 58 and a withdrawal of the hook 56 from the keeper opening 46.This downward pivoting of the lower plate 74 is to be effected by anexpansion of the air sack or bag 68, with the expansion of the sack 68resulting from the forced movement of the contained air from the sack 70through an interconnecting air hose 92. The forced movement of air is indirect response to a compression of the sack 70 which is to be locatedin the vicinity of the ball or toe portion of the foot or foot member 90associated with the leg 10. The sack 70 is to be located on the lowerportion of the foot 90 so as to compress or receive the weight oftheuser immediately prior to the toe portion of the foot leaving the groundas the weight is being thrown to the other leg and as the artificial legis about to be raised from the ground. In this manner, as the foot 9.0leaves the ground the lower leg member 14' is free to swing rearwardlyand then forwardly in the manner of ear end portion 60 pivotally ,anormal leg. Once the foot 90 leaves the ground, the

pressure on the sack 70 is released and the' smooth upper edge of thehook 56 is resiliently biased against the bearing plate 52 by the coilspring 66 with this coil spring 66 possessing a sufficient strength soas to engage the hook 56 upon an alignment of;the hook 56 with thekeeper hole 46 along with aresultant compressioneof:

full weight of the user has been transferred-to the toe portionimmediately prior'to a r'aisin'g'of this toe portion" as noted supra.

The instant invention also contemplates theprovision of means wherebythe force necessary to release the latch 10 may be adjusted or varied asmight-be required.

Toward this end, a bulbtypehand pump 94 is provided in communication,through anlair hose 96 and a Y-connector 98, with the air hose 92. Thisair pump 94 is seated within a recess or housing 100 defined within theforward wall of the. lower legmember 14,from, which it may be withdrawnduring use. When it is desired to reduce the amount of pressure on thebag 70 needed to release the latch 58, air is pumped into the sack andhose system 68, 70 and-92 so as to further expand the bag 68 which inturn results in a lowering of the plate 74 and a partial withdrawal ofthe latch hook, 56. By the same token, when it is desired to increasethe weight needed to release the, latch, an amount. of air may bewithdrawn from the air sack system. In order to effect this introductionand release of air, it will of course be apprecitaed that the hand pump94 is to be provided with an appropriate valve construction 102,including means for selectively retaining air within the system andbleeding air therefrom.

In order to provide a gauge for indicating the pressure within thesystem, anv opening or window 104- is provided through the front wall ofthe lower leg member 14. in alignment with the plate legs 82. Thiswindow 104 is surrounded by a plate-like member 106 having a verticalscale thereon with which an indicating bar 108 will register, this bar108 being fixed, through a pair of rearwardly directed legs, to theupper ends of the vertical legs 82 so as to v indicate the verticalposition of the plate 74 and, through the scale on the plate 106,indicate the contained pressure to which this vertical positioncorresponds;

From the foregoing, it will be appreciated that a unique joint lock andcontrol have been defined with the release of the lock occurring beyondthe fiat foot position when the weight is shifted to the toe portion ofthe footl In this manner, a firm leg is provided when thewearer of theleg is merely standing, with there being no danger of the jointunlocking until the wearer actually begins to walk. In walking, or forthatjmatter running, the joint unlocks as the weight is shifted to thetoe immediately prior to the foot leaving the ground so as to allow fora. free swinging of the lower leg member until just prior to anengagement of the heel, the locking of the 'lower'leg memberautomatically occurring upon a forward swinging of this member asnormally occurs'during movement. The actual disengagement of the latchthrough the utilization of a pneumatic sy'stem is' deemed particularlyunique an'rlconstitutes an extremely lightweight and economical controlsystem which can in fact be adapted to various lock arrangements ln"conjunction with this pneumatic control system, it, will use beappreciated that an adjustme'h' t thereof can beleasily eife'cted throuh a conventional val've' hand pump incorporated therein andfstgre'ddirectly withinftheleg itself.

The foregoing is con 'dered fa s illustrativeonly" of't hc prl'rieiplesoftheinveiitionfFurther, since numerousmo'difications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be restored to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. An artificial limb and joint lock control therefor, said limbcomprising first and second limb members, means pivotally joiningadjacent ends of said limb members and defining a joint constructiontherewith, a keeper fixed to the first limb member, a latch movablymounted on the second limb member and selectively engageable with thekeeper, means resiliently biasing said latch toward engagement with saidkeeper, and pressure responsive means for disengaging said latch, saidpressure responsive means including a first expandable fluid sackpositioned in the vicinity of the latch, a pressure member engaged withsaid first sack and movable in response to an expansion of said firstsack, link means engaged be tween said pressure member and said latchfor effecting a movement of the latch in response to a movement of thepressure member, a second expandable fluid tight sack mounted remotefrom said first sack on an exposed surface of said limb for selectivecompressive engagement against an external object, and a fluid hosecommunicating said sacks for the transfer of fluid therebetween.

2. The construction of claim 1 including means for varying the fluidpressure with the system defined by the first and second sacks and thefluid hose.

3. The construction of claim 2 wherein said pressure responsive means ispneumatic, said means for varying the pressure comprising a hand pumpcommunicated with the fluid hose, and means on said second limb memberfor receiving and storing said hand pump.

4. The construction of claim 3 wherein said first and second limbmembers respectively comprise upper and lower leg members, said definedjoint constituting the knee joint, said lower leg member having a footthereon, said foot having a forward toe portion, said second sack beingmounted on and exposed beneath the toe portion of said foot.

5. In a joint lock and control for an artificial leg including upper andlower leg members, a vertical mount positionable between said members,means adapted for pivotally engaging the upper end of said mount withthe upper member, means adapted for fixing the lower end of the mount tothe lower member, a latch pivotally mounted on said mount, means engagedbetween said latch and said mount for resiliently biasing said latch ina first locking direction, a pressure member pivotally mounted relativeto said mount, an expansible member engaged between said mount and saidpressure member for effecting, upon an expansion thereof, an outwardpivotal movement of said pressure member, and link means engaged betweensaid pressure member and said latch for moving said latch in a secondreleasing direction against the biasing force in response to an outwardpivotal movement of said pressure member.

6. The construction of claim 5 wherein said expansible member is an airbellows, a second air bellows remote from the first bellows, an air hosecommunicating said first and second bellows, and a pressure varying pumpcommunicated with said air hose.

7. An artificial leg and a knee joint lock control therefor, said legcomprising upper and lower leg members, said upper leg member having aninternal chamber opening downwardly through the lower end thereof, saidlower leg member having an internal chamber opening upwardly through theupper end thereof, a vertically elongated mount extending across theadjoining ends of said members and into the respective chambers, saidmount having a rearwardly directed portion on the lower end thereofengaged against the rear wall of the lower leg chamber, means of rigidlyfixing the lower end of the mount to the lower leg member within thechamber therein, means pivotally mounting the upper end of the mountwithin the upper chamber, a keeper fixed to the lower end of the upperleg member forwardly of the vertical mount, said keeper having a keeperhole defined therein, a forwardly projecting latch extending forwardlyfrom the mount below the lower end of the upper leg member, meanspivotally mounting the rear end of the latch on the mount for movementin a vertical plane, a venically directed hook on the forward end of thelatch selectively engageable within the keeper hole upon a ver ticalalignment of said leg members, spring means engaged between the rear endof the latch and a fixed abutment therebelow for resiliently biasing thehook end of the latch upwardly towards seated engagement with the keeperhole, a pressure plate underlying the lower end of the mount, saidpressure plate being oriented generally horizontally, means hingedlyengaging the rear end of the pressure plate relative to the mount for apivotal movefent of the pressure plate in a vertical plane, link meansengaged between the free forward edge of the pressure plate and the hookdefining forward end of the latch, and a pressure responsive expandablemember positioned be tween the lower end of the mount and the pressureplate whereby an expansion thereof will effect a downward pivoting ofthe pressure plate and a corresponding downward pivoting of the latchagainst the biasing force of the spring means. 1

8. The construction of claim 7 wherein said link means include a rigidvertical portion on the forward end of said pressure plate, a forwardlyprojecting indicator on said rigid portion, a viewing window through theforward part of the lower leg member exposing the indicator, and agraduated scale on the exterior of said lower leg member providing avisual indication of the state of expansion of the expandable member.

9. The construction of claim 8 wherein said expandable member comprisesan air sack, a foot including a forwardly projecting toe portion beingmounted on the lower end of the lower leg member, a second air sacksecured to the under surface of the toe portion of the foot forselective engagement with the ground, an air hose communicating the airsacks for allowing a transfer of air from the second foot mounted sackto the first mentioned sack in response to a compression of the footmounted sack for effecting a pivotal movement of the pressure plate anda disengagement of the latch.

10. The construction of claim 9 including a hand pump, an elongated airhose communicating the hand pump with the first mentioned air hose, anda forwardly opening housing in the lower leg member selectivelyreceiving and storing said hand pump.

References Cited UNITED STATES PATENTS 951,989 3/1910 Hanger 3--82,485,036 10/1949 Christopher 327 XR 2,522,853 9/1950 Black 327 XR2,537,351 1/1951 Johnson et al. 327 XR 2,629,876 3/1953 Fullerton et al.3-l.2 2,870,453 l/ 1959 Vasquez 326 2,943,622 7/ 1960 Nelson 327 XRFOREIGN PATENTS 633,838 10/ 1927 France.

RICHARD A. GAUDET, Primary Examiner.

R. L. FINKS, Assistant Examiner.

5. IN A JOINT LOCK AND CONTROL FOR AN ARTIFICIAL LEG INCLUDING UPPER ANDLOWER LEG MEMBERS, A VERTICAL MOUNT POSITIONABLE BETWEEN SAID MEMBERS,MEANS ADAPTED FOR PIVOTALLY ENGAGING THE UPPER END OF SAID MOUNT WITHTHE UPPER MEMBER, MEANS ADAPTED FIXING THE LOWER END OF THE MOUNT TO THELOWER MEMBER, A LATCH PIVOTALLY MOUNTED ON SAID MOUNT, MEANS ENGAGEDBETWEEN SAID LATCH AND SAID MOUNT FOR RESILIENTLY BIASING SAID LATCH INA FIRST LOCKING DIRECTION, A PRESSURE MEMBER PIVOTALLY MOUNTED RELATIVETO SAID MOUNT, AN EXPANSIBLE MEMBER ENGAGED BETWEEN SAID MOUNT AND SAIDPRESSURE MEMBER FOR EFFECTING, UPON AN EXPANSION THEREOF, AN OUTWARDPIVOTAL MOVEMENT OF SAID PRESSURE MEMBER, AND LINK MEANS ENGAGED BETWEENSAID PRESSURE MEMBER AND SAID LATCH FOR MOVING SAID LATCH IN A SECONDRELEASING DIRECTION AGAINST THE BIASING FORCE IN RESPONSE TO AN OUTWARDPIVOTAL MOVEMENT OF SAID PRESSURE MEMBER.